Since the first postage meter was invented by Mr. Arthur H. Pitney at the turn of the century, the postage meter had a rather steady evolution until the late 1970's. During this long period, the postage meter was basically a mechanical device involving a printing means with ascending and descending registers. The meter could be charged with a fixed amount of postage and there could be accounting of the amount of postage that had been used as well as a record of the amount of postage remaining. What is commonly referred to as a postage meter is actually two separate units, the postage meter and the base or mailing machine. Although the base is also referred to as the mailing machine, as used in this specification the term mailing machine includes the postage meter and drive means therefor. The postage meter is that portion of the device that has the printing dies as well as the ascending and descending registers. The base is that portion of the device that supplies drive to the postage meter portion. The reason for making this device in two separable units was because the postage meter portion had to be brought to a post office periodically in order to have more postage charged to such meter. It obviously would be less of a task to carry the postage meter part of the machine without having to bring the drive portion as well. For this reason, the heavier parts of the machine were located in the base.
With the advent of the dynamic growth in the field of electronics, the postage meter has experienced radical changes by the development of the electronic postage meter. Whereas previous postage meters had relied almost exclusively on mechanical systems, the recently developed electronic postage meters perform tasks such as setting, accounting and printing through electromechanical and electronic means. In order to accomplish such tasks, electronic postage meters have utilized central processing units, memories, counters and the like for the purpose of performing tasks that had previously been performed mechanically. The first electronic postage meters paralleled the prior mechanical meters in that they were designed to fit upon a base. In fact, the first electronic postage meters were designed so that they could be placed upon bases that had been designed for mechanical meters and which were readily available. With the companion advancement of the remote meter resetting systems, it is no longer necessary that the mailing machine be separated into two distinct units since the necessity of taking the meter to the post office for recharging has been eliminated. As a consequence, it would be desirable to have a self-contained electronic mailing machine that includes the metering function as well as all drive mechanisms that are controlled by electronic means. Obviously, such a device would be lighter, more compact, and more economical to produce.
In prior electronic postage meters, a date door was provided with a switch associated therewith whereby upon opening of the door the switch would be actuated and the meter would be initialized. Such activity took place upon "power up", i.e., power being supplied to the meter during start-up. These switch-door combinations posed a potential safety hazard in that if the meter were tripped while the door was open, an operator's fingers could be caught and injury could result therefrom.